Water shortages have long been known in a number of areas in this country, and for that matter the world. Often, under water shortage conditions, water users have been requested or required to reduce water consumption. In a typical family household, daily water usage may be substantial, the typical household including a variety of water consuming devices, such as sinks, tubs, showers, dish and clothes washers, toilets and utility water outlets for lawn watering and so forth. Most families find it difficult to substantially reduce water consumption except on pain of inconvenience and consistent attention on the part of all family members to avoid unnecessary running of fresh water.
It has been recognized that in the typical household, water is used only once before discarding (draining to the sewer or septic tank for example) and that consumption of fresh water can be reduced by reuse of at least a portion of the incoming supply of water to the household before discarding. For example, U.S. Pat. Nos. 3,318,449 (Jennings) and 3,112,497 (Call) suggest systems in which household water consuming devices are essentially separated into two classes. The first involves devices such as kitchen and bathroom sinks, clothes and dishwashers, tubs and showers, and the like which are to be supplied with fresh water at most only lightly contaminated, as by soaps, detergents and so forth, and which for convenient reference is hereafter termed "gray water". The other class of device, on the other hand, normally includes toilets, for which the water input need not be fresh and which for health reasons are to drain directly to a septic tank, sewer line or the like. This second class of device may also include outlets for lawn sprinkling or other uses which can be performed as efficiently by gray water as fresh. In these systems, gray water drained from sinks, washers, etc. is kept in a tank and supplied on demand to toilets for flushing purposes. Reid U.S. Pat. No. 3,594,825 discloses basically a variation on the Jennings patent and is not believed to require separate discussion.
While these systems provide for a reduction in water wastage, by at least partial use of gray water, the present invention is intended to improve thereover by eliminating certain difficulties and unsatisfactory characteristics present in such systems.
In both Jennings and Call, gray water, as long as supplied from a gray water source (e.g. sink) will continue to flow into the gray water holding tank independent of tank water level, and thus even if the tank is full. Excess gray water entering the tank necessarily overflows, and thus requires an overflow drain pipe connected from the interior of the gray water holding tank to the sewer line, such that excess water supplied to the tank normally overflows from the holding tank to the sewer line. To minimize a build-up of solids in the holding tank, it is known such systems to provide a filter in the gray water drain line leading to the holding tank.
Disadvantages of such systems, overcome by the present invention, include risk of overflow of the holding tank (which may go unnoticed for sometime due to typical location of the tank in the basement in an out-of-the-way place) upon clogging of the tank overflow drain line, or more seriously, due to plugging of the sewer line downstream of the tank overflow drain line. In the latter instance, even should the holding tank not overflow, there is risk of contamination with sewer water of the holding tank, the gray water drain line feeding same and all devices provided gray water from such holding tank (e.g. toilet flush tanks, lawn watering hydrants, etc.).
Such known systems, due to the continuous connection of the gray water storage tank to the sewer line through the overflow conduit, appear to risk, in addition, backflow of sewer gas into the home from the tank. On the other hand, an attempt to seal the tank to avoid this problem risks contamination of a fresh water make-up line leading to the tank in the event of blockage of the tank overflow drain line, or downstream portions of the sewer line. Further, for proper operation of the tank overflow drain line in conducting excess gray water to the sewer line, the latter should be below the bottom of the holding tank and care must be taken to avoid siphoning of water from the sewer line into the gray water holding tank when gray water is removed from the holding tank, as to fill a toilet flush tank.
Accordingly, the objects of this invention include provision of:
A used water reuse system including means responsive to the water level in the gray water holding tank for determining whether gray water sources will then drain to the holding tank or instead to the sewer line, such that maximum tank level is controlled without recourse to an overflow drain.
A system as aforesaid in which valves, controlled by tank water level, determine flow from gray water source drains as between the tank and the sewer line and wherein a fail-safe valve operates to prevent excess filling of the tank in the event of failure of one of such valves.
A system as aforesaid in which said drain valves and fail-safe valve are pressure fluid operated and in which operating pressure fluid is obtained from a pressurized gray water line supplied by a pump on the output side of the gray water holding tank and leading to points of gray water use such as a toilet flush tank.
A system as aforesaid in which gray water pump action is initiated by sensing a reduction in pressure in the output line thereof as would normally result from demand by a gray water using device.
A system as aforesaid in which fresh water can be supplied to the gray water holding tank, for make-up purposes, in response to sensing of a holding tank level falling so low as to approach the tank outlet to the pump.
Further objects and purposes of the invention will be apparent to persons acquainted with systems of this type upon reading the following specification and inspecting the accompanying drawings.